Inserter instrument and implant clip

ABSTRACT

A method and apparatus assisting safe one-handed insertion of an implant. An implant implantation device has a frame which includes a trigger mechanism, an outer sleeve mechanically coupled to the frame, an inner shaft having a grabber for mechanically engaging an implant, the inner shaft slidably disposed within the outer sleeve, and a retaining element disposed over the inner shaft for directing the grabber toward a closed position. An implant clip has a first member, a second member pivotally coupled to the first member, a first implant holder pivotally coupled to the first member, the coupling causing the implant clip to have a closed position and an open position, and a second implant holder, the second implant holder pivotally coupled to the second member, a surface of the first implant holder and a surface of the second implant holder remaining substantially parallel to each other while the first member and the second member pivot between the closed position and the open position.

BACKGROUND OF THE INVENTION

Spinal surgery involves many challenges as the long-term health andmobility of the patient often depends on the surgeon's technique andprecision. One type of spinal surgery involves the removal of a damageddisc that is located between adjacent vertebral bodies. Procedures areknown in which the damaged disc is replaced with an artificial disc orspinal fusion cage.

The artificial disc or spinal fusion cage includes protrusions forengaging the adjacent vertebral bodies to aid in the initial fixation ofthe artificial disc or spinal fusion cage. These protrusions are oftensharp and can injure the surgeon's hand, if contacted, duringimplantation.

The insertion of an article, such as the artificial disc or fusion cage,presents the surgeon with several challenges. The adjacent vertebralbodies collapse upon each other once the damaged disc is removed. Thesebodies must be separated to an extent sufficient to enable the placementof the prosthesis. However, if the vertebral bodies are separated, ordistracted, to beyond a certain degree, further injury to the patientcan occur. The artificial disc should also be properly positionedbetween the adjacent vertebral bodies. Over-insertion posteriorly, orunder-insertion anteriorly of the prosthesis can lead to pain, posturalproblems and/or limited mobility or freedom of movement.

Specialized tools have been developed to facilitate the placement ofdevices, such as artificial discs, between adjacent vertebral bodies ofa patient's spine. Among the known tools for performing such proceduresare spinal distractors and insertion devices. However, use of thesetools to distract the vertebral bodies and insert the artificial disc orspinal fusion cage can prove cumbersome.

Exemplary devices for installing prostheses and/or grafts betweenvertebral bodies are disclosed in U.S. Pat. Nos. 5,431,658 and5,505,732. U.S. Pat. No. 5,431,658 discloses a facilitator device forthe insertion of bone grafts between two adjacent vertebrae. Thedisclosed tool has two flat, tong-like guides that distract thevertebrae as a screw-type inserter forces the graft between thedistracted vertebrae. U.S. Pat. No. 5,505,732 discloses an apparatus anda method of inserting implants. The intervertebral space is firstdistracted and a hollow sleeve having teeth at one end is then driveninto the vertebrae that are adjacent the disc space. A drill is thenpassed through the hollow sleeve, removing the disc and the bone inpreparation for receiving the implant, which is then inserted throughthe sleeve. These devices are both operated with two-hands and do notprovide safety features for preventing injury to a surgeon.

Despite existing tools and technologies, there remains a need for animproved device to facilitate insertion of an artificial disc or aspinal fusion cage.

SUMMARY OF THE INVENTION

The invention is generally related to a method and apparatus forassisting in a safe one-handed insertion of an implant. An implantimplantation device including (i) a frame which includes a triggermechanism, (ii) an outer sleeve mechanically coupled to the frame, (iii)an inner shaft having a grabber for mechanically engaging an implant,the inner shaft slidably disposed within the outer sleeve and (iv) aretaining element for directing the grabber toward a closed position.The grabber can be removably coupled to the inner shaft. The retainingelement can be a spring.

Optional elements can include a knob, a drag adjustment screw, at leastone protrusion, and a depth control member. The knob can be mechanicallycoupled to the outer sleeve for causing the outer sleeve and the innershaft to be rotated about the frame. The drag adjustment screw canprovide tension between the trigger mechanism and the inner shaft. Theat least one protrusion can be located on the outer sleeve for slidablyengaging a distraction instrument. The depth control member can beslidably coupled to the outer sleeve for providing a predeterminedinsertion depth of the implant.

The grabber is provided to hold the implant during insertion of theimplant between the vertebrae. The grabber includes grabber tips formechanically engaging the implant. The grabber tips can have a varietyof shapes. For example, the grabber tips can be dovetailed in shape orcan include a first pair of slots for engaging a first tab of theimplant and a second pair of slots for engaging a second tab of theimplant. The first pair of slots can be different in size from thesecond pair of slots. A sizing slot can be located between the firstpair of slots and second pair of slots to allow for a variation of taband grabber slot dimensional differences.

The grabber also can include at least one marking to identify a positionof the implant in relationship to the patient. The marking can be a pinlocated on a surface of the grabber. The marking can be a plurality ofmachined slots on a surface of the grabber.

There is also provided an implant clip for aligning an implant endplateradially, providing a lordotic angle for implantation, packaging theimplant, holding the implant during the implant sterilization process,and protecting the surgeon from being cut by protrusions on a surface ofthe implant. The implant clip, includes (i) a first member; (ii) asecond member pivotally coupled to each other, the coupling causing theimplant clip to have a closed position and an open position, (iii) afirst implant holder pivotally coupled to the first member, and (iv) asecond implant holder, the second implant holder pivotally coupled tothe second member, a surface of the first implant holder and a surfaceof the second implant holder remaining substantially parallel to eachother while the first member and the second member pivot between theclosed position and the open position. The first member and the secondmember can be shells. The implant clip can also include a spring fordirecting the implant clip toward a closed position.

Each holder can define a depression, where each depression is angledwith respect to its holder. Each depression can also be made from aconformable material. The second holder can include a pair of pins thatslidably engage a respective pair of cylindrical cavities in the firstholder, thereby causing the surface of each holder to remainsubstantially parallel to each other while the first member and thesecond member pivot between the closed position and the open position.Alternatively, the first holder and the second holder can include arespective pin and a respective cylindrical cavity that slidably engageeach other, thereby causing the surface of each holder to remainsubstantially parallel to each other while the first member and thesecond member pivot between the closed position and the open position.Each holder can also include at least one alignment protrusion foraligning of an implantation instrument with the implant clip.

A method of inserting the implant into an intervertebral space includes(i) loading an implant in an implant clip, (ii) mechanically engaging animplantation instrument to the implant and (iii) removing the implantfrom the implant clip. The implant can be an artificial disc or spinalfusion cage.

Loading an implant in an implant clip includes (i) opening the implantclip, (ii) inserting the implant into the implant clip, and (iii)closing the implant clip.

Mechanically engaging the implantation instrument to the implantincludes (i) opening a grabber located on an end of the implantationinstrument, (ii) aligning the grabber with the implant, and (iii)closing the grabber to mechanically engage the grabber to the implant.

The method further includes (iv) distracting a prepared disc space witha distraction instrument, (v) inserting the implant into the prepareddisc space with the implantation instrument, (vi) releasing the implantfrom the implantation instrument, and (vii) removing the implantationinstrument and distraction instrument.

Inserting the implant into the prepared disc space includes aligning theimplantation instrument with the distraction instrument.

The invention has many advantages. For example, the invention providessafe one-handed insertion of an implant into a prepared disc space. Theinvention reduces the amount of time required to complete the surgicalprocedure. The invention also provides for various manipulations of theimplant without physically contacting the implant. For example, theinvention can align an endplate of the implant radially and provide alordotic angle for implantation, the invention can be used for packagingthe implant, and the invention can be used to hold the implant duringthe implant sterilization process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a cross-sectional view of an insertion instrument of thepresent invention.

FIG. 1B shows a plan view of the insertion instrument of FIG. 1A.

FIG. 2A shows a perspective view of one embodiment of a grabber of thepresent invention.

FIG. 2B shows a perspective view of another embodiment of a grabber ofthe present invention.

FIG. 2C shows a perspective view of yet another embodiment of a grabberof the present invention.

FIG. 3A shows a perspective view of one embodiment of an implant clip ofthe present invention.

FIG. 3B shows a side view of the implant clip of FIG. 3A.

FIG. 3C shows a perspective view of another embodiment of an implantclip the of present invention.

FIG. 3D shows a side view of the implant clip of FIG. 3B in an openposition.

FIG. 3E shows a perspective view of a shell of the implant clip of FIG.3A.

FIG. 3F shows a perspective view of a grabber aligned with a pair ofimplant holders.

FIG. 3G shows a perspective view of a pair of implant holders of theimplant clip of FIG. 3C.

FIG. 3H shows a cutaway perspective view of a pair of implant holders ofthe implant clip of FIG. 3A.

FIG. 31 shows a perspective view of the implant clip of FIG. 3B attachedto the grabber of FIG. 2C.

FIG. 4 shows a perspective view of an artificial disc.

FIG. 5 shows a perspective view of the insertion instrument of FIG. 1engaged to an implant enclosed in the implant clip of FIG. 3A.

FIG. 6A shows perspective view of the artificial disc of FIG. 4 engagedto the grabber of FIGS. 2A.

FIG. 6B shows perspective view of another type of implant engaged to thegrabber of FIGS. 2B and 2C.

FIG. 7 shows a perspective view of the artificial disc of FIG. 4 beinginserted into a prepared disc space using the insertion instrument ifFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The same number appearingin different drawings represents the same item. The drawings are notnecessarily to scale, with emphasis instead being placed uponillustrating the principles of the invention.

In general, the present invention is related to apparatus and method forsafely inserting an implant into a prepared disc space. The implant canbe an artificial disc or spinal fusion cage. Referring to FIGS. 1A and1B, insertion instrument 100 is shown in a side cross-sectional view anda plan view, respectively. Insertion instrument 100 includes frame ordriver body assembly 110, actuator assembly 126 and grabber 160 (FIG.2A-2C). Insertion instrument 100 is a normally closed device, that is,grabber 160 is normally substantially contained within actuator assembly126.

Actuator assembly 126 includes outer sleeve 130, inner shaft 140, andretaining pin 148. Outer sleeve 130 includes a tapered end 175 whichslidably engages tapers 163 on grabber 160 (FIG. 2A-2C), allowing forcompression and expansion of the grabber 160 when in use. Inner shaft140 includes female threaded end 142 and male threaded end 144. Femalethreaded end 142 mates with spring retaining screw 152 and male threadedend 144 mates with grabber 160. Internal compression spring 150 isfastened to actuator assembly 126 and held in place by spring retainingscrew 152. Once actuator assembly 126 is assembled, it is inserted intodriver body assembly 110 and retained within assembly 110 with retainingpin 148. Optional knob 170 can be mechanically attached to outer sleeve130 to allow outer sleeve 130 and inner shaft 140 to rotate about driverbody assembly 110. Optional guides 171 can be attached to outer sleeve130 to slidably mate with spinal disc distraction instrument 950 (FIG.7). Depth control member 173 can also be fixedly or slidably attached onouter sleeve 130 for providing a predetermined insertion depth of theimplant.

Driver body assembly 110 includes handle 112, handle transition 114,strike boss 116, trigger mechanism 120, and pivot pin 122. Triggermechanism 120 can be any type of trigger mechanism known in the art.Trigger mechanism 120 pivots about pivot pin 122 in driver body assembly110. When trigger mechanism 120 is “squeezed” toward handle 112, grabber160 (FIG. 2A-2C) extends from actuator assembly 126 and expands torelease or attach to an implant. When trigger mechanism 120 is released,grabber 160 recedes into actuator assembly 126 and compresses, therebyengaging the implant or returning to its normally closed position.Optional drag adjustment screw 124 is rotatably coupled to driver bodyassembly 110 for adjusting the drag force between trigger mechanism 120and spring retaining screw 152 of actuator assembly 126.

FIGS. 2A-2C show various grabbers 160 of the present invention. Eachgrabber 160 includes grabber tips 162 for mechanically engaging theimplant. Grabber tips 162 may be various shapes and sizes depending uponimplant selection. As shown, grabber tips 162 may be slot shaped 162 a,162 b or dovetailed shaped 162 c, 162 d. Grabber tips 162 can engageimplants having multiple heights. It should be understood grabber tips162 can be any shape which can engage any type of implant. In analternative embodiment, inner shaft 140 and grabber 160 can be oneembodiment.

Each grabber 160 includes female threaded hole 161 for mating to malethreaded end 144 of inner shaft 140 of actuator assembly 126. It shouldbe understood that any means known in the art can be used to attachgrabber 160 to inner shaft 140.

Each grabber 160 includes tapers 163 and relatively longexpansion/compression slot 164 to allow grabber 160 to expand andcompress during use. FIGS. 2A-2C show grabber 160 in the expandedposition. Each grabber 160 also includes sizing slot 166 to allow for avariation of tab and grabber slot dimensional differences.Expansion/compression slot 169 (FIG. 2B) is an alternative embodiment ofsizing slot 166.

Cephalad markers 168 can be included on a surface of grabber 160 toallow the user to determine the position of the implant. Markers 168 canbe pin 168 a or machined slots 168 b.

FIGS. 3A-3I show details of implant clip 300. Implant clip 300 can beused to align the implant radially and provide a lordotic angle forimplantation, can be used for implant packaging, can be used to hold theimplant during the implant sterilization process, and can protect thesurgeon from being cut by protrusions on the surface of the implant.Implant clip 300 includes a pair of symmetrical shells 306, 308,superior implant holder 312, inferior implant holder 318, and spring302. In another embodiment, shells 306, 308 can be any type of memberwhich can hold the implant.

Each shell 306, 308 includes spring holder 301, pivot member 310, pivothole 311, and a pair of holder holes 314. Each pivot member 310snappingly and pivotally engages pivot hole 311 of opposing shells 306,308. Spring 302 is connected between shells 306, 308 and maintained inplace by spring holders 301. Spring 302 maintains implant clip 300 in anormally closed position, as shown in at least FIGS. 3A and 3B.

In one embodiment, as shown in FIGS. 3A, 3D, 3F, and 3H, superiorimplant holder 312 includes a pair of alignment protrusions 316, a pairof protrusion members 317, a pair of position poles 324, and implantdepression 315. Inferior implant holder 318 includes a pair of alignmentprotrusions 322, a pair of protrusion members 317, a pair of positionholes 326, and implant depression 321. In another embodiment, as shownin FIGS. 3C and 3G, superior implant holder 312 and inferior implantholder 318 can be symmetrical for ease of production.

Position poles 324 slidably engage position holes 326 such that surfaces327, 329 remain substantially parallel to each other while implant clip300 moves between a closed position as shown in FIGS. 3A-3C and an openposition as shown in FIG. 3D. It should be understood that any methodcan be employed to maintain holders 312, 318 parallel to each other.Once each holder 312, 318 is slidably engaged to each other, protrusionmember 317 of each holder 312, 318 snappingly and pivotally engages apair of holder holes 314 in respective shells 306, 308. Shells 306, 308can be made from a nylon-based plastic or other material known in theart which allows shells 306, 308 to be snappingly engaged to each other.Holders 312, 318 are typically made from injection moldable, gammasterilizable hard plastics, such as Radel, Carbon Fiber, Peek, andAcrylonitrile Butadiene Styrene (ABS). However, holders 312, 318 can bemade from any material known in the art which can protect the implantfrom damage.

Implant depressions 315, 321 are made to accept a plurality of implantsof different shapes and sizes. Implant depressions 315, 321 can beangled with respect to holders 312, 318 to provide a lordotic angle forthe implant. Implant depressions 315, 321 can also be conformable toaccept a plurality of implants. Alternatively, implant depressions 315,321 can be rigid to accept individual respective implants.

Alignment protrusions 316, 322 of implant clip 300 cause properalignment of grabber 160 (FIGS. 2A-2C) with engagement protrusions 712,722 of artificial disc 330 (FIG. 4). Alignment protrusions 316, 322 canform alignment slot 323 as shown in at least FIG. 3A or an alignmentwindow 325 as shown in FIGS. 3C and 3G.

FIG. 31 shows a perspective view of the implant clip of FIG. 3B attachedto the grabber of FIG. 2C. Grabber 160 is in a closed position (i.e.,trigger released) within outer sleeve 130 of insertion instrument 100.Grabber tips 162 c are shown engaged to engagement indents 906 onartificial disc 900 which is contained within holders 312, 318 ofimplant clip 300.

The operation of insertion instrument 100 and implant clip 300 will beexplained with reference to the figures. Although reference is made toan artificial disc 330, its principles are applicable to spinal fusioncages.

In operation, a user opens (FIG. 3C) implant clip 300 by depressing andholding opposite portions of shells 306, 308 at opposite ends of spring302 (FIG. 3B) to an open position as shown in FIG. 3D. Opened clip 300is placed over a selected artificial disc 330, causing implant holders312, 318 to engage artificial disc 330 when shells 306, 308 arereleased.

In one embodiment, the user aligns grabber 160 (FIG. 2A) of implantationinstrument 100 with alignment slot 323 on implant clip 300. Oncealigned, the user squeezes trigger mechanism 120 (FIG. 1) onimplantation instrument 100, thereby causing grabber tips 162 a, 162 bto be inserted over engagement tabs 712, 722 on artificial disc 330(FIG. 4). Once grabber tips 162 are inserted over engagement tabs 712,722, the user releases trigger mechanism 120, causing grabber tips 162to engage engagement tabs 712, 722 on artificial disc 330 as shown inFIG. 5. The user removes implant clip 300 from artificial disc 330 byopening and removing implant clip 300 from the now engaged artificialdisc 330, as shown in FIG. 6A.

In another embodiment, the user aligns grabber 160 (FIGS. 2B and 2C) ofimplantation instrument 100 with alignment window 325 on implant clip300. Once aligned, the user squeezes trigger mechanism 120 (FIG. 1) onimplantation instrument 100, thereby causing grabber tips 162 c, 162 dto be inserted over engagement indents 906 on artificial disc 900 (FIGS.31 and 6B). Once grabber tips 162 are inserted over engagement indents906, the user releases trigger mechanism 120, causing grabber tips 162to engage engagement indents 906 on artificial disc 900 (FIG. 31). Theuser removes implant clip 300 from artificial disc 900 by opening andremoving implant clip 300 from the now engaged artificial disc 900, asshown in FIG. 6B.

As shown in FIG. 7, distraction instrument 950 is inserted over pins(not shown) that are secured into vertebral bodies 962, 964. Artificialdisc 330 is passed between the forks of distraction instrument 950 usingimplantation instrument 100 (FIGS. 1A-1B). In an alternate embodiment,guides 170 on insertion instrument 100 slidably engage slots in theforks of distraction instrument 950 to help the user guide artificialdisc 330 into prepared disc space 970. Once artificial disc 330 is in adesired location within prepared disc space 970, the user squeezestrigger mechanism 120 (FIG. 1A) which releases artificial disc 330 inprepared disc space 970. The user can determine the desired position byobserving cephalad markers 168 (FIGS. 3A-3B) located on a surface ofgrabber 160. In an alternative embodiment, implantation instrument 100can include depth control member 173 (FIG. 1A) such that artificial disc330 can be inserted into prepared disc space 970 at a predetermineddepth.

Implantation instrument 100 and distraction instrument 950 are removed,causing superior vertebra 962 and inferior vertebra 964 to engageartificial disc 330.

Equivalents

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. An implant implantation device, comprising: (i) a frame having atrigger mechanism; (ii) an outer sleeve mechanically coupled to theframe; (iii) an inner shaft having a grabber for mechanically engagingan implant, the inner shaft slidably disposed within the outer sleeve;and (iv) a retaining element for directing the grabber toward a closedposition.
 2. The device of claim 1, wherein the retaining element is aspring.
 3. The device of claim 1, further including a knob mechanicallycoupled to the outer sleeve, the knob causing the outer sleeve and theinner shaft to be rotated about the frame.
 4. The device of claim 1,further including a drag adjustment screw rotatably coupled to the framefor providing tension between the trigger mechanism and the inner shaft.5. The device of claim 1, further including at least one protrusion onthe outer sleeve for slidably engaging a distraction instrument.
 6. Thedevice of claim 1, further including a depth control member slidablycoupled to the outer sleeve, the depth control member for providing apredetermined insertion depth of the implant.
 7. The device of claim 1,wherein the grabber includes grabber tips for mechanically engaging theimplant.
 8. The device of claim 7, wherein the grabber tips aredovetailed in shape.
 9. The device of claim 7, wherein the grabber tipsinclude a first pair of slots for engaging a first engagement tab of theimplant and a second pair of slots for engaging a second engagement tabof the implant.
 10. The device of claim 9, wherein the first pair ofslots are different in size from the second pair of slots.
 11. Thedevice of claim 9, wherein a sizing slot is located between the firstpair of slots and the second pair of slots to allow for a variation oftab and slot dimensional differences.
 12. The device of claim 1, whereinthe grabber includes at least one marking to identify a position of theimplant.
 13. The device of claim 12, wherein the marking is a pinlocated on a surface of the grabber.
 14. The device of claim 12, whereinthe marking is a plurality of machined slots on a surface of thegrabber.
 15. The device of claim 1, wherein the grabber is removablycoupled to the inner shaft.
 16. An implant clip, comprising: (i) a firstmember; (ii) a second member pivotally coupled to the first member, thecoupling causing the implant clip to have a closed position and an openposition; (iii) a first implant holder, the first implant holderpivotally coupled to the first member; and (iv) a second implant holder,the second implant holder pivotally coupled to the second member, asurface of the first implant holder and a surface of the second implantholder remaining substantially parallel to each other while the firstmember and the second member pivot between the closed position and theopen position.
 17. The implant clip of claim 16, wherein the firstmember and the second members are shells.
 18. The implant clip of claim16, wherein each holder defines a depression.
 19. The implant clip ofclaim 18, wherein each depression is angled with respect to its holder.20. The implant clip of claim 18, wherein each depression is made of aconformable material.
 21. The implant clip of claim 16, furtherincluding a spring located between the first member and the secondmember, the spring directing the implant clip toward the closedposition.
 22. The implant clip of claim 16, wherein the second holderincludes a pair of pins that slidably engage a respective pair ofcylindrical cavities in the first holder, thereby causing the surface ofeach holder to remain substantially parallel to each other while thefirst member and the second member pivot between the closed position andthe open position.
 23. The implant clip of claim 16, wherein the firstholder and the second holder includes a respective pin and a respectivecylindrical cavity that slidably engage each other, thereby causing thesurface of each holder to remain substantially parallel to each otherwhile the first member and the second member pivot between the closedposition and the open position.
 24. The implant clip of claim 16,wherein each holder includes at least one alignment protrusion foraligning of an implantation instrument with the implant clip.
 25. Amethod of inserting an implant, comprising the steps of: (i) loading animplant in an implant clip; (ii) mechanically engaging an implantationinstrument to the implant; and (iii) removing the implant from theimplant clip.
 26. The method of claim 25, wherein the step of loading animplant in an implant clip includes: (i) opening the implant clip; (ii)inserting the implant into the implant clip; and (iii) closing theimplant clip.
 27. The method of claim 25, wherein the step ofmechanically engaging the implantation instrument to the implantincludes: (i) opening a grabber located on an end of the implantationinstrument; (ii) aligning the grabber with the implant; and (iii)closing the grabber to mechanically engage the grabber to the implant.28. The method of claim 25, further including the steps of: (iv)distracting a prepared disc space with a distraction instrument; (v)inserting the implant into the prepared disc space with the implantationinstrument; (vi) releasing the implant from the implantation instrument;and (vii) removing the implantation instrument and distractioninstrument.
 29. The method of claim 28, wherein the step of insertingthe implant into the prepared disc space includes aligning theimplantation instrument with the distraction instrument.
 30. The methodof claim 25, wherein the implant is an artificial disc or a spinalfusion cage.